Yeah? Ever seen step-by-step switchers?
Yes I have. Many of my earliest central offices were still loaded with Strowger switches. A few still had panels and cord boards. I've even had the opportunity to "unstick" a few and burnish the contacts. The SXS switches are pretty noisy. You can hear when a customer seizes the lines, then listen for the center armature the click, click, click upward with each pulse. Next, it rotates with pulses to connect to the next level. Poetry in motion...and pretty noisy. The "fine motion" crossbar switches make very little noise in comparison. The electronic space-time-space switches (all electronic fabric) can switch 100,000 calls in non-blocking fashion and total silence.
The most impressive lab technology I saw in 1981 was an opto-mechanical phone. It had no external power or batteries. The laser light coming down the fiber provided the power. The handset included a "speaker" with interlaced semi-annular rings. Each ring had a surface area proportial to the bit weight of the 8-bit PCM sample. Mixing of the waveform occur in the air space between the surface of the rings and the ear of the user. The phone was light as a feather. I don't think that will ever be deployed outside of a laboratory setting. Getting fiber optic to the door step is just scratching the surface right now.
Another "cute" laboratory invention will probably find its way into big switches. It involves a 3 dimensional switching of a bitstream through a solid medium. An X-Y grid of inputs appears on one face of a cube. The incoming beam is "steered" to an outgoing face by manipulating the frequency of the optical carrier and the amplitude of the optical carrier. Refraction occurs to two planes to reach the output. No moving parts. The technical challenge when I last check up on the concept was achieving enough refraction in each plane to have a usable size of output ports.